The invention relates to a shovel for an excavator in general.
The digging edge of the shovels of excavators, which are also described, for example, as scoops, according to their shape, are provided with projecting teeth. These comprise tooth retainers which are secured to the edge of the shovel spaced apart from one another and tooth tips made of a highly-wear-resistant material which are attached to the tooth retainers in such a manner that they can be replaced. In order also to protect the edge of the shovel against wear in the gaps between the teeth, instead of using a build-up weld of highly wear-resistant material, which is expensive to replace and can involve difficulties, it is customary to fit the areas of the shovel edge between the teeth with replaceable caps made of a relatively wear-resistant material. It is not suitable in practice to secure the caps with screws or other similar fastenings which are pushed through holes in the wall of the shovel because of the great disadvantage that the stability or strength of the front edge of the shovel, which has to absorb the high working forces acting on the teeth, is appreciably impaired by the fastening holes. A different fastening method, in which the tooth tips are designed with lateral projections such that by means of these projections and positive locking the tooth tips hold the caps between them and keep them pressed against the edge of the shovel, requires the tooth tips to be specially designed. It has the advantages that the caps have to fit the spaces between the teeth and, in the direction in which the tooth tips are put into place, they have to match the fastening position of the tooth tips on the tooth retainers. Also it has the disadvantage that in order to replace the caps the tooth tips also have to be removed from the tooth retainers and in addition the securing devices between the tooth tips and the tooth retainers have to be removed. U.S. Pat. No. 3,995,384 discloses a shovel having a fastening for replaceable parts of the cutting edge, in the case of which, however, the parts of the cutting edge are uniform plates with a large width in the direction of the shovel edge. These cutting edge plates are secured against being pulled off the shovel edge, by a securing bolt which is pushed in parallel to the upper surface and the front edge of the wall of the shovel between the retaining piece on the shovel wall and a tongue-like hooked extension of the cutting edge plate projecting away over the retaining piece. This securing means is not suitable for securing the caps in a shovel and cannot be used for that purpose since the retainers for the teeth that extend to a relatively great length beyond the shovel wall lie at a short distance from each side of a cap and there is no room for a securing bolt insertable on the cap parallel to the surface of the shovel wall. There is also the danger that a securing bolt wedged between the retaining piece and the hooked extension and secured against longitudinal displacement by friction may become loose and fall out as a result, for example, of jarring of the shovel occurring during operation, with the result that the cutting edge parts would fall off the shovel edge.